1 files changed, 47 insertions, 0 deletions
diff --git a/cli/ops/fs.rs b/cli/ops/fs.rs
index 63b3ad7f5..9ca4b31ae 100644
--- a/cli/ops/fs.rs
+++ b/cli/ops/fs.rs
@@ -36,6 +36,7 @@ pub fn init(i: &mut CoreIsolate, s: &State) {
   i.register_op("op_link", s.stateful_json_op(op_link));
   i.register_op("op_symlink", s.stateful_json_op(op_symlink));
   i.register_op("op_read_link", s.stateful_json_op(op_read_link));
+  i.register_op("op_ftruncate", s.stateful_json_op2(op_ftruncate));
   i.register_op("op_truncate", s.stateful_json_op(op_truncate));
   i.register_op("op_make_temp_dir", s.stateful_json_op(op_make_temp_dir));
   i.register_op("op_make_temp_file", s.stateful_json_op(op_make_temp_file));
@@ -785,6 +786,52 @@ fn op_read_link(
 
 #[derive(Deserialize)]
 #[serde(rename_all = "camelCase")]
+struct FtruncateArgs {
+  promise_id: Option<u64>,
+  rid: i32,
+  len: i32,
+}
+
+fn op_ftruncate(
+  isolate_state: &mut CoreIsolateState,
+  state: &State,
+  args: Value,
+  _zero_copy: &mut [ZeroCopyBuf],
+) -> Result<JsonOp, OpError> {
+  state.check_unstable("Deno.ftruncate");
+  let args: FtruncateArgs = serde_json::from_value(args)?;
+  let rid = args.rid as u32;
+  let len = args.len as u64;
+
+  let resource_table = isolate_state.resource_table.clone();
+  let is_sync = args.promise_id.is_none();
+
+  if is_sync {
+    let mut resource_table = resource_table.borrow_mut();
+    std_file_resource(&mut resource_table, rid, |r| match r {
+      Ok(std_file) => std_file.set_len(len).map_err(OpError::from),
+      Err(_) => Err(OpError::type_error(
+        "cannot truncate this type of resource".to_string(),
+      )),
+    })?;
+    Ok(JsonOp::Sync(json!({})))
+  } else {
+    let fut = async move {
+      let mut resource_table = resource_table.borrow_mut();
+      std_file_resource(&mut resource_table, rid, |r| match r {
+        Ok(std_file) => std_file.set_len(len).map_err(OpError::from),
+        Err(_) => Err(OpError::type_error(
+          "cannot truncate this type of resource".to_string(),
+        )),
+      })?;
+      Ok(json!({}))
+    };
+    Ok(JsonOp::Async(fut.boxed_local()))
+  }
+}
+
+#[derive(Deserialize)]
+#[serde(rename_all = "camelCase")]
 struct TruncateArgs {
   promise_id: Option<u64>,
   path: String,